Stein-D rolled bridge

[Terry]

I'm surprised no one has posted to this. I shouldn't be the last word on
this, but I'll give it what it got.

First of all, bridges don't roll anywhere (assuming the bridge is still
glued to the soundboard). Either the cap was cut this way at the factory
(hard to imagine, but.....), or the soundboard has deformed. Stretch that
string on the bottom side of the soundboard between every accessible rib. If
the soundboard is deformed, you will likely find some crown (maybe a lot) on
the back side of the bridge, and either less, no or reverse crown between
the long bridge and the belly rail.

Check real close to see if the crown is even on both sides of the bridge.

If the soundboard is deformed, it should be replaced, IMHO. Have fun getting
the manufacturer to agree.   :-(

If there is actually nice even crown everywhere on the board, perhaps they
actually built this thing with an improperly carved bridge cap (no, tell me
it ain't so...). In that case, perhaps a new bridge cap actually would
remedy the problem.

How does the piano sound (besides a buzzing back scale)?

I had a new piano from this same group and it had a full 1/4-inch of reverse
crown to the soundboard. The piano sounded okay. The manufacturer expressed
no willingness to address the reverse crown at all. As a matter of fact,
when I called the manufacturer (this was before I went into piano
technology) to ask if the soundboard should be crowned convex toward the
strings, three of four technical experts did not know if or which way their
soundboard should be crowned. Incidentally, this particular belly had plenty
of positive downbearing!

Keep us informed. Sounds interesting! Good luck.

Terry Farrell

>    Approx. 3 year old Steinway D
>    Appears to have a severely rolled bridge.
>
> Measurements.......
>   With a dial gauge I measure plus 10 at the back
> and 0 at the front at about D4. At about D5 0 bearing.
> Most readings are lower at the front then back
> throughout.
>
>   So I call in a friend with a proper bubble gauge who
> gets results consistent with mine. At D4 plus 24 at
> back, negative 12 front.
>
>   Of added significance may be that the bass bridge
> has roll; Negative 15 front, on second highest bass
> bridge note.
>
>   What motivated me to measure was buzzing back scale
> on the chrome plates, as if the rear of the bridge
> had lifted enough to eliminate good contact with the
> plate. Termination points do not stay seated, more
> buzzing has appeared over the winter.
>
>   There is still some crown on the board, as seen
> by a stretched string, but the bridge has rolled
> forward.
>
> Questions
>
>    This is a relatively new piano, so a warranter
> issue.
> What should be done?
> What is likely to be suggested?
> What arguments can be had against half measures?
>
>    If they suggest just recapping the bridges.
> They should do it; correct?
> Would such a solution be a band aid to a more serious
> soundboard problem?